What's the difference between biological and artificial evolution?
Biological and artificial evolution work around pretty much the same principles.

Fitness and selection: In biology, the fittest organisms in an ecosystem are more likely to survive long enough to reproduce, passing on their genes in the process. In artificial evolution, our organisms are in fact solutions to our problem, which can be evaluated to determine how good they are (their fitness). We choose ourselves which solutions will be selected for reproduction (there are many ways to do this selection, but what is common among all of them is that the fittest solutions have a higher chance of being selected).

Crossover: In biology, an organism inherits a portion of each parent's genes, so is a sort of genetic hybrid of both parents. For artificial evolution, a new solution (a "child" solution) will inherit part of its parent's solutions (we take a partial solution from each parent, and glue those partial solutions together to construct a new solution).

Mutation: In nature mutations often occur at birth and this is why there are many different species. Harmful mutations make the individual less likely to survive long enough to pass them on to children, and in contrast helpful mutations make it more likely that the individual will survive long enough to pass them unto children. The same can be said for artificial evolution: A mutation randomly changes a small part of the solution, and if it makes that solution fitter, then that solution has a higher chance of being selected for reproduction.